My 1999 Sportaman 335 cuts out at high engine speed while moving pretty fast. I checked fuel filter, took carb a part
to clean, but no dirt in it. When you are at full throtle
it starts to lay down on you, as soon as you let up to about
3/4 thortle starts to pull hard again. I took fuel pump apart it looks ok, but ordered new diaphram any way. It did this some last summer on long rides but after I got it real wet and muddy, but would clear up by self. Any help would be
great guys.[img]i/expressions/face-icon-small-confused.gif[/img]

 

Your 335 pulls hard?? Let alone any at all? I once had a 335 and it was just way too gutless.
Anyway, sounds like the main jet if you're having probs w/ 3/4 and up.

 

Check the snorkel for the airbox where it goes up by the fuel tank. The intake from the factory was cut so that if you sit on the seat just right it will seal against the tank choking the air flow. If it is that way just take a knife and modify it.